In recent years, organic light-emitting diode (OLED) display panels gradually become a mainstream in display panels due to their advantages of high contrast, self illumination and the like, and are very popular.
In a large-sized OLED display panel, in order to protect the stability of the channel layer in the thin film transistor (TFT), a layer of metal pattern is formed under the top-gate thin film transistor to avoid the interference of external light on the characteristics of the thin film transistor. However, since the metal pattern and the channel layer are separated by a buffer layer, and metal wires in the large-sized OLED display panel are very dense, the light reflected by other metal regions cannot be blocked, and thus the stability of the thin film transistor is reduced.